3.5 Active Transport

Describe the proton pump

the proton pump from the breakdown of ATP to move Hydrogen ions (or protons) out of the cell. This makes a concentration gradient of the Hydrogen ions (H+), which makes the fluid outside of the cell more positively charged than the fluid inside.

What does exocytosis do in the human body?

Ex: Your big toe; your brain sends a message that travels through a series of nerve cells to reach your toe. This nerve impulse travels along each nerve cell as an electrical signal, but must be converted to a chemical signal to cross the tiny gap that separates one nerve cell from another, These chemicals are stored in the vesicles with nerve endings.

Describe active transport

Active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration; uses transport proteins powered by chemical energy; cells use active transport to get needed molecules regardless of the concentration gradient and to maintain homeostasis.

Ions are low in concentration outside a cell. They move rapidly into the cell via protein molecules. What term describes this action? Does it require energy?

Active transport drives molecules across a membrane from a region of lower concentration to higher concentration; similar to an escalator; uses energy.

Under what conditions would a molecule need to be actively transported across a membrane?

Active transport goes against the concentration gradient. Instead of being a channel it pumps ATP which converts into ADP and gets glucose in.

How does active transport move molecules against the concentration gradient?

Active transport proteins can use chemical energy to move a substance against its concentration gradient.

Why do cells use active transport?

Cells use active transport to get needed molecules regardless of the concentration gradient and to maintain homeostasis

Suppose molecules were unable to diffuse into and out of cells. How might life be different if cells had to use active transport to move every substance? Explain your reasoning.

Cells would require much more amounts of energy than they already do to perform all functions. which would have to take in more food to provide more energy

How do transport proteins that are pumps differ from those that are channels?

Channels, when they open, just allow the molecule to pass through. With a pump, it requires energy and will move it in a which direction.

Small lipid molecules are in high concentration outside a cell. They slowly cross the membrane into the cell. What term describes this action? Does it require energy?

Diffusion is the movement of a molecule from high concentration to low concentration - it takes no energy, it just does it.

How do endocytosis and exocytosis differ from diffusion?

Endocytosis and exocytosis involve taking something into the cell (endo) or removing it from the cell (which), but it doesn't move across the membrane via diffusion, it requires energy and is either taken in as a little membrane-bound package or removed.

Describe the sodium potassium pump

The sodium-potassium pump uses energy directly from the breakdown of the ATP. It pumps three sodium ions out of the cell for every two potassium ions it pumps in.

What might happen if your vesicles in your neurons were suddenly unable to fuse with the cell membrane?

The vesicle wouldn't be able to expel its contents resulting in some nerve functions being severed.

How do cells move large molecules in and out of the cell?

Transport in vesicles lets substances enter or exit a cell without crossing through the membrane.

Do you think endocytosis and exocytosis can occur within the same cell? Explain your reasoning.

Yes, endocytosis and exocytosis can occur in the same cell. it's how a cell transports and exports material in and out.

Describe exocytosis

a process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane.

What is phagocytosis?

a type of endocytosis in which the cell membrane engulfs large particles

Describe endocytosis

endocytosis is the process of taking liquids of fairly large molecules into a cell by engulfing them in a membrane. In this process, the cell membrane makes a pocket around a substance. The pocket breaks off inside the cell and forms a vesicle, which then fuses with a lysosome or a similar type of vesicle.

What does phagocytosis do for the immune system?

macrophages help your body fight infection. They find foreign materials such as bacteria and engulf and destroy them.

What do protein pumps do ?

protein pumps move contents from lower concentrations to higher concentrations